In the field of electronic communications, an electronic signal of known frequency propagates over a signal transmission line of known dielectric constant. The transmission line may be required to provide a shift in the phase of the signal by a small and precise amount, for example, to adjust the signal with a desired phase angle.
For a fixed frequency signal, a phase shift through a transmission line is dependent upon the electrical length of the transmission line. The electrical length, in turn, is dependent upon the physical length of the transmission line and the dielectric constant of the transmission line.
It is known to provide a phase shift along a transmission line of unchanging dielectric constant, by providing a lengthened or shortened transmission line.
A desired phase shift along a transmission line can be accomplished by coupling a phase shifter in the form of an electrical connector along the transmission line, as an alternative to the known technique of lengthening or shortening the transmission line. To provide a phase shift, for example, to adjust a signal of fixed frequency to a desired phase angle, one connector must be selected from a supply of connectors. If the different electrical lengths are produced by connectors of different physical lengths, the length of the connector selected would cause a corresponding variation in the physical length of the transmission line.
An advantage would reside in an electrical connector constructed for achieving a variable electrical length within a constant or fixed physical length. Connectors of the same physical length could be interchanged with one another to produce a phase shift within a relatively wide range without lengthening or shortening the transmission line. Adjustment of the phase shift to a desired phase angle can be accomplished by interchanging the connectors without increased consumption of space allowed along the transmission line for the connector.
U.S. Pat. No. 3,757,278 discloses a known connector assembly having an elongated center contact concentrically surrounded by two dielectric sleeves spaced apart along a center contact, and supporting the center contact concentrically within a conductive connector housing. The known connector assembly is not intended to be a phase shifter, and particularly, not a phase shifter having a fixed physical length and a variable electrical length.
An object of the invention is to provide a phase shifter by design in the form of an electrical connector.
Another object is to provide a phase shifter in the form of an electrical connector having a fixed physical length and a variable electrical length.